Propagation measurement of a partially open drain: An examination of the LOS and NLOS sections

This paper presents field measurement results collected from inside a partially open drain at 2.4 GHz, a frequency band that is commonly deployed for wireless local area networks. The motivation of this paper stems from the need to better understand the behaviour of radio waves in partially open drain environments, in terms of signal coverage and attenuation characteristics. Partially open drains are a common sight in several Asian countries. Their design and shapes are similar to a certain degree to that of tunnels, except that they have one less reflecting wall on top. This is one major difference compared to the drainage systems in the US and Europe because the drainage systems in those regions are primarily below ground and covered. Previous research in this area has shown that the existence of the partially open drains makes up an additional channel in which the radio signal can travel. In this work, we are interested to further scrutinize the partially open drain environment in two sections, namely the line-of-sight (LOS) and non-line-of-sight (NLOS) sections using an empirical approach. Towards this end, one Data Acquisition Unit (DAU) has been assembled and tested to be used for data collection. Field measurements were taken at intervals of 30cm using two dipole antennas that were oriented for vertical-vertical polarization. In this paper, the repeatability of the measurement results that was verified by consecutive measurements is reported. Besides, discussion and insights are offered to analyze the measurement results collected from inside a partially open drain at LOS and NLOS sections. The direct research output of this work is highly relevant to the wireless communications systems design in many Asian cities, where partially open drains dominate.